Question

What impulse occurs when an average force of 20-N is applied by a dad to a new bike riding child for 3.5 s. b) What change in momentum does the new bike rider undergo? c) If the combined mass of the bike and the child is 32 kg and the child was initially at rest, calculate the final speed.

Answer 1

Answer:

A. 70 Ns

B. 70 Kgm/s

C. 2.19 m/s

Explanation:

A. Determination of the impulse.

Force (F) = 20 N

Time (t) = 3.5 s

Impulse (I) =?

Impulse (I) = force (F) × time (t)

I = Ft

I = 20 × 3.5

I = 70 Ns

Thus, the Impulse is 70 Ns.

B. Determination of the change in momentum

Force (F) = 20 N

Time (t) = 3.5 s

Change in momentum =?

Change in momentum = m(v – u) = Ft

Change in momentum = Ft

Change in momentum = 20 × 3.5

Change in momentum = 70 Kgm/s

C. Determination of the final velocity.

Change in momentum = 70 Kgm/s

Initial velocity (u) = 0 m/s

Combined mass (m) = 32 kg

Final velocity (v) =?

Change in momentum = m(v – u)

70 = 32(v – 0)

70 = 32(v)

70 = 32v

Divide both side by 32

v = 70 / 32

v = 2.19 m/s

Thus, the final velocity is 2.19 m/s